PULPING CHEMISTRY AND KINETICS OF RDH (RAPID DISPLACEMENT HEATING) PROCESS

The pulping chemistry and kinetics of RDH (Rapid Displacement Heating) process were studied with laboratory experiments and theoretical simu lations. It was shown that both alkalinity and sulfidity of the warm a nd hot black liquor used in displacement procedures are critical to RD H pulping. Low alkalinity in either the warm or hot black liquor resul ts in a higher bulk to residual delignification transition point. The shifted transition point RDH pulping kinetics at low Kappa numbers. Lo w sulfidity in either the warm or hot black liquor reduces significant ly the bulk delignification rate in RDH pulping.